Abstract Body (Do not enter title and authors here): Background: Calcification is a well-established prognostic marker for coronary artery disease. However, its implications for renal artery stenosis are not well understood, particularly in patients with renovascular hypertension and impaired renal function undergoing revascularization.

Objective: To investigate the impact of CKD stage and renal artery calcification assessed by intravascular ultrasound (IVUS) on renal functional outcomes after the revascularization in patients with renovascular hypertension.

Methods: We conducted a retrospective analysis of patients with renovascular hypertension due to unilateral renal artery stenosis. All procedures were performed stent implantation under the guidance of IVUS. Plaque burden, presence of calcification, calcium arc, and stent area were assessed by IVUS. Patients were stratified into two groups based on their pre-procedural estimated glomerular filtration rate (eGFR): high-stage CKD (HS-CKD; eGFR ≧45 mL/min/1.73 m²) and low-stage CKD (LS-CKD; eGFR <45 mL/min/1.73 m²). Renal functional outcome was measured using delta eGFR, calculated as the difference between baseline and 1-year post-procedural eGFR. Associations between IVUS findings and delta eGFR were assessed in both the HS-CKD and LS-CKD groups.

Results: A total of 33 patients (63.6% male, mean age 74.6 ± 9.1 years) were included. The follow-up duration was similar between the HS-CKD (n=13) and LS-CKD (n=20) groups (366 [267 to 381] vs. 356 [255 to 384] days, p=0.61). There was no significant difference in IVUS-derived vessel area, percent plaque area, and minimum stent area between the two groups. Renal artery calcification on IVUS was detected in 46.1% of the HS-CKD group and 65.0% of the LS-CKD group (p=0.28). In the HS-CKD group, the delta eGFR did not differ significantly between patients with and without calcification (−2 [−13 to 4] vs. 8 [−4 to 11.5] mL/min/1.73 m², p=0.25). However, in the LS-CKD group, patients without calcification had a significantly lower delta eGFR than those with calcification (−4 [−6 to 1.5] vs. −1 [−2 to 8] mL/min/1.73 m², p=0.04). No significant association was observed between calcium arc and delta eGFR in either group.

Conclusion: In patients with renovascular hypertension due to unilateral renal artery stenosis, the presence of renal artery calcification has a potential association with renal function after revascularization, regardless of the degree of calcification, especially in those with lower stage CKD.